<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script src="jquery.min.js"></script>
</head>
<body>
<ul>
    <li>导航123</li>
    <li id="t2">导航123123</li>
    <li>导航33333</li>
    <li id="t4">导航55555</li>
</ul>

<script type="text/javascript">
<!--    方法一 获取事件对象 js-->
    var t2 = document.getElementById('t2');
    t2.style.color = 'red';

//    方法二 jq
    $('#t4').css('color','yellow')
</script>
</body>
</html>